package org.jianfa.learn.threadpool;

import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.threadpool.support.fixed.FixedThreadPool;

import java.util.Map;
import java.util.concurrent.*;

public class WatchingThreadPool extends FixedThreadPool implements Runnable {

    private static final double ALARM_PERCENT = 0.90;
    private final Map<URL, ThreadPoolExecutor> THREAD_POOLS = new ConcurrentHashMap<>();
    public WatchingThreadPool() {
        //每隔3秒打印线程使用情况
        Executors.newSingleThreadScheduledExecutor().scheduleWithFixedDelay(
                this, 1, 3, TimeUnit.SECONDS
        );
    }

    //通过父类创建线程池
    @Override
    public Executor getExecutor(URL url) {
        final Executor executor = super.getExecutor(url);
        if (executor instanceof ThreadPoolExecutor) {
            THREAD_POOLS.put(url, (ThreadPoolExecutor)executor);
        }
        return executor;
    }

    @Override
    public void run() {
        //遍历线程池
        for (Map.Entry<URL, ThreadPoolExecutor> threadPoolExecutorEntry : THREAD_POOLS.entrySet()) {
            final URL url = threadPoolExecutorEntry.getKey();
            final ThreadPoolExecutor threadPoolExecutor = threadPoolExecutorEntry.getValue();
            //计算相关指标
            final int activeCount = threadPoolExecutor.getActiveCount();
            final int poolSize = threadPoolExecutor.getCorePoolSize();
            double usedPercent = activeCount / (poolSize * 1.0);
            System.out.println("线程池执行状态: activeCount:" + activeCount + " poolSize:" + poolSize + " usedPercent:" + usedPercent);
            if (usedPercent > ALARM_PERCENT) {
                System.out.println("超出警戒线！ host: " + url.getIp() + " 当前使用率是:" + usedPercent);
            }
        }
    }
}
